Auxin herbicidal mixtures

Abstract

Herbicidal mixtures comprising an auxin herbicide and an adjuvant comprising a salt having a quaternary ammonium cation and/or a phosphonium cation are described. The adjuvant reduces the volatility of the auxin herbicide and/or counteracts the negative impact on the volatility of the auxin herbicide caused by the addition of a co-herbicide. Methods of preparing the herbicidal mixtures are also described.

What is claimed is: 
     
       1. A method of preparing a herbicidal mixture, the method comprising:
 combining an auxin herbicide comprising a first cation, a co-herbicide selected from the group consisting of glyphosate, glufosinate, and combinations thereof, and an adjuvant comprising a salt comprising a second cation, wherein the salt is selected from the group consisting of: 
 (a) an ammonium salt of Formula I 
 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each butyl and X is an agronomically acceptable anion;
 (b) a salt containing a nitrogen heterocycle of Formula II 
 
       
         
           
           
               
               
           
         
       
       wherein A is a 5 or 6-membered heterocyclic ring; R 5  is a C 1 -C 20  alkyl; R 6  is hydrogen or a C 1 -C 6  alkyl, and X is an agronomically acceptable anion;
 (c) a phosphonium salt of Formula III 
 
       
         
           
           
               
               
           
         
       
       wherein R 7 , R 8 , R 9 , and R 10  are independently a C 1 -C 12  hydrocarbyl and X is an agronomically acceptable anion; and mixtures thereof,
 wherein the acid equivalent weight ratio of co-herbicide to auxin herbicide is from about 1:1 to about 5:1; 
 wherein the molar ratio of auxin herbicide to salt of Formula I, II, and/or III is from about 1:3 to about 3:1; and 
 wherein the herbicidal mixture has a total herbicide concentration no greater than about 40% by weight acid equivalent (a.e.). 
 
     
     
       2. A method of reducing off-site movement of an auxin herbicide following application to the foliage of auxin-susceptible plants of a herbicidal mixture comprising an auxin herbicide, the method comprising:
 preparing the herbicidal mixture according to the method of  claim 1 ; and 
 applying the herbicidal mixture to the foliage of the auxin-susceptible plants. 
 
     
     
       3. The method of  claim 2  wherein the herbicidal mixture comprises a salt of dicamba and the auxin-susceptible plants are growing in and/or adjacent to a field of crop plants, the crop plants comprising transgenic crop plants comprising a dicamba-tolerance trait. 
     
     
       4. A herbicidal mixture, comprising:
 an auxin herbicide comprising a first cation, a co-herbicide selected from the group consisting of glyphosate, glufosinate, and combinations thereof, and an adjuvant comprising a salt comprising a second cation, wherein the salt is selected from the group consisting of: 
 (a) an ammonium salt of Formula I 
 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each butyl and X is an agronomically acceptable anion;
 (b) a salt containing a nitrogen heterocycle of Formula II 
 
       
         
           
           
               
               
           
         
       
       wherein A is a 5 or 6-membered heterocyclic ring; R 5  is a C 1 -C 20  alkyl; R 6  is hydrogen or a C 1 -C 6  alkyl, and X is an agronomically acceptable anion;
 (c) a phosphonium salt of Formula III 
 
       
         
           
           
               
               
           
         
       
       wherein R 7 , R 8 , R 9 , and R 10  are independently a C 1 -C 12  hydrocarbyl and X is an agronomically acceptable anion; and mixtures thereof,
 wherein the acid equivalent weight ratio of co-herbicide to auxin herbicide is from about 1:1 to about 5:1; 
 wherein the molar ratio of auxin herbicide to salt of Formula I, II, and/or III is from about 1:3 to about 3:1; and 
 wherein the herbicidal mixture has a total herbicide concentration no greater than about 40% by weight acid equivalent (a.e.). 
 
     
     
       5. The herbicidal mixture of  claim 4  wherein:
 R 7 , R 8 , R 9 , and R 10  are independently C 1 -C 12  alkyl; and/or 
 the salt of Formula III comprises tetrabutylphosphonium chloride. 
 
     
     
       6. The herbicidal mixture of  claim 4  wherein X is Cl, Br, or OH. 
     
     
       7. The herbicidal mixture of  claim 4  wherein the auxin herbicide is selected from the group consisting of 3,6-dichloro-2-methoxybenzoic acid (dicamba); 2,4-dichlorophenoxyacetic (2,4-D); 4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB); 2-(2,4-dichlorophenoxy)propanoic acid (dichloroprop); 2-(4-chloro-2-methylphenoxy)acetic acid (MCPA); 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB); 4-amino-3,6-dichloro-2-pyridinecarboxylic acid (aminopyralid); 3,6-dichloro-2-pyridinecarboxylic acid (clopyralid); 2-[(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid (fluroxypyr); [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr); 2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop); 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid (picloram); 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); 6-amino-5-chloro-2-cyclopropyl-4-pyrimidinecarboxylic acid (aminocyclopyrachlor); agriculturally acceptable salts or other derivatives of any of these herbicides; racemic mixtures and resolved isomers thereof; and mixtures thereof. 
     
     
       8. The herbicidal mixture of  claim 4  wherein the auxin herbicide comprises a salt of dicamba selected from the group consisting of the monoethanolamine salt, diethanolamine salt, isopropylamine, diglycolamine salt, potassium salt, sodium salt, dimethylamine salt and mixtures thereof. 
     
     
       9. The herbicidal mixture of  claim 4  wherein the auxin herbicide comprises a salt of 2,4-D. 
     
     
       10. The herbicidal mixture of  claim 4  wherein the co-herbicide comprises a salt of glyphosate selected from the group consisting of the potassium salt, monoammonium salt, diammonium salt, sodium salt, monoethanolamine salt, n-propylamine, isopropylamine, ethylamine, dimethylamine, ethylenediamine, hexamethyldiamine, and trimethylsulfonium salt and mixtures thereof. 
     
     
       11. The herbicidal mixture of  claim 4  wherein the pH of the herbicidal mixture is from about 4 to about 5.5. 
     
     
       12. The herbicidal mixture of  claim 4  wherein the herbicidal mixture further comprises a surfactant selected from the group consisting of alkoxylated tertiary etheramines, alkoxylated quaternary etheramines, alkoxylated etheramine oxides, alkoxylated tertiary amines, alkoxylated quaternary amines, alkoxylated polyamines, sulfates, sulfonates, phosphate ethers, alkyl polysaccharides, alkoxylated alcohols, amidoalkylamines and combinations thereof. 
     
     
       13. The herbicidal mixture of  claim 4  wherein the herbicidal mixture is a concentrate composition wherein the total herbicide content is from about 10 wt. % a.e. to about 40 wt. % a.e. 
     
     
       14. The herbicidal mixture of  claim 4  wherein the herbicidal mixture is an application mixture wherein the total herbicide content is from about 0.1 wt. % a.e. to about 10 wt. % a.e. 
     
     
       15. The herbicidal mixture of  claim 14  wherein the co-herbicide in the application mixture is from about 0.5 wt. % a.e. to about 8 wt. % a.e. 
     
     
       16. The herbicidal mixture of  claim 14  wherein the concentration of the auxin herbicide in the herbicidal mixture is from about 0.25 wt. % (a.e.) to about 4 wt. % (a.e.). 
     
     
       17. The herbicidal mixture of  claim 4  wherein the concentration of the adjuvant in the herbicidal mixture is from about 0.1 wt.% to about 10.0 wt. %. 
     
     
       18. The herbicidal mixture of  claim 4  wherein the molar ratio of auxin herbicide to salt of Formula I, II, and/or III is from about 1:1 to about 3:1. 
     
     
       19. The herbicidal mixture of  claim 4  wherein the adjuvant comprises an ammonium salt of Formula I 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each butyl and X is an agronomically acceptable anion. 
     
     
       20. The herbicidal mixture of  claim 19  wherein X is Cl. 
     
     
       21. The herbicidal mixture of  claim 19  wherein X is Br. 
     
     
       22. The herbicidal mixture of  claim 19  wherein X is OH. 
     
     
       23. The herbicidal mixture of  claim 19  wherein the molar ratio of auxin herbicide to salt of Formula I is from about 1:1 to about 3:1. 
     
     
       24. The herbicidal mixture of  claim 4  wherein the adjuvant comprises a salt containing a nitrogen heterocycle of Formula II 
       
         
           
           
               
               
           
         
       
       wherein A is a 5 or 6-membered heterocyclic ring; R 5  is a C 1 -C 20  alkyl; R 6  is hydrogen or a C 1 -C 6  alkyl, and X is an agronomically acceptable anion. 
     
     
       25. The herbicidal mixture of  claim 24  wherein:
 A is a substituted imidazole ring, a substituted pyridine ring, or a substituted pyrrolidine ring; 
 R 5  is C 1 -C 12  alkyl; and/or 
 the salt of Formula II is selected from the group consisting of 1-butyl-1-methyl-pyrrolidinium chloride, 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, cetylpyridinium chloride, and cetylpyridinium bromide. 
 
     
     
       26. The herbicidal mixture of  claim 4  wherein the adjuvant comprises a phosphonium salt of Formula III 
       
         
           
           
               
               
           
         
       
       wherein R 7 , R 8 , R 9 , and R 10 are independently a C 1 -C 12  hydrocarbyl and X is an agronomically acceptable anion. 
     
     
       27. The herbicidal mixture of  claim 26  wherein:
 R 7 , R 8 , R 9 , and R 10  are independently C 1 -C 12  alkyl; and/or 
 the salt of Formula III comprises tetrabutylphosphonium chloride.